The three languages I speak are native Dutch, English and Japanese. I think knowing three languages is nice, but I'd like to learn one more in the future because out of the ones I know English is the only one widely used globally. Maybe French. German, Spanish and Portugese are useful too. It might be fun to learn another Asian language like Indonesian but it's just not that practical compared more internationally relevant languages (no offense, my native language is also like this). Until now I've poured all my time and effort into learning Japanese properly so I never interacted too much with other languages since secondary education but now that I'm at a more comfortable level I feel I can try to breach out more without saboting my Japanese studies. I remember in secondary school when I took French and Spanish simultenously I was mixing up the two all the time lol.